Dash-pot.



No, 725,656. PATENTED APR. 21,1903. 'W. 0. BEAUVAIS.

DASH POT.

APPLICATION FILED AUG. 4, 1902..

H0 MODEL.

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UNITED STATES PATENT OFFICE;

WILLIAM COLLIER BEAUVAIS OF NEW ORLEANS, LOUISIANA.

- DA S H- POT.

SPECIFICATION forming part-0f Letters Patent Iva 725,656, dated April 21, 1903.

Application filed August 4, 1902. Serial No. 118,244.; (No motleld Toall whom it may concern:

Be it known that 1, WILLIAM COLLIER BEAUVAIS, a citizen of the UnitedStates, residing in New Orleans, in the parish of Orleans and State ofLouisiana, have invented a new and useful Improvement in Dash-Pots,; ofwhich the following is a specification.

This invention relates to the construction of dash-pots used with thegovernorsof'slowrunning Corliss engines, and is especially valuablewhere the load on the engine is heavy at times and light at other times;Of course it may be used in other places where the requirements aresimilar.

The object of the invention is toprevent the governor from hunting, asit is calledthat is to say, from moving unevenly orrin a jerky orirregular manner. 7

The object of my invention is obtained by providing the dash-pot with anair-chamber in which a body of air is imprisoned by the oil throughwhich the piston travels, the oil having access to the air-chamber atthe bottom and acting alternately to compress and release the air ateach full stroke of the piston. The air-chamber is preferably an annularone and surrounds the dash-pot.

The nature of the invention will be more fully understood from thedescription given below and from the accompanying drawings, in which- 7Figure 1 is a vertical section of my improved dash-pot, and Fig. 2 is asection on the line 2 2 of Fig. 1.

In said drawings, 3 represents the piston of the dash-pot, attached tothe tubular 'stem i.

The piston has a central oil-passage 5,scom- Vber communicating with thepiston-chamber municating with a flaring recess 6, which allows the oilto move through the piston, and ports 7 are provided in the stem andcommunicate with the recess 6. The stem is adj ustably attached to anoperating-rod 8, extending up to the governor and also extending downwithin the stem to the bottom thereof, where it acts as a valveto-regulate the capacity of the ports 7. The relative adjustment of thestem and rod may be obtained in any suitable way-as, for instance,byvthreadingtherod at 9 and threading the stem interiorly, so it mayengage the thread 9and the adjustment may be rendered secure by thejam-nut 10.

The piston traverses the cylinder 11, which is always full of oil, inthe usual manner, the speed of the movement depending on the size of-theports 7. Cylinder 11 is open at the bottom and isplaced inside anothercylinder 12, an annular chamber 13 being formed between thet'wo.Cylinder 12'has a bottom 14, and the 'chan1be1 13 is closed at the top,as shown at 15. Having no outlet at the top, it will be seen that theair in the chamber 13 will be trapped bytheoil. A cover 16 is placedover cylinder 11 and may be secured by screws 17, and the piston stempasses through such cover. 1

The chamber 13 communicates at its bottom with the piston-chamber, andpreferably this 7 communication is established by suspending cylinder 11in cylinder 12, above the bottom of the latter, as indicated in thedrawings. -In this" manner free opportunity is given the oil to movefrom one cylinder to the other in accordance with the direction ofmovement of the piston. When the piston moves down, it creates pressureupon the oil below'it and forces more or less of it into the annularair-chamber, so that it compresses the imprisoned air in the upper partof the latter; The. imprisoned air is thus caused to exert agradually-increasing resistance to the piston, so that its stroke endsgradually and without jar or shock. When the piston moves up, it willgradually relieve the compression on the air and after relieving it willtend to create a vacuum in the air-chamber, and thereby to retard orgradually slow the upstroke.

I claim- '1. The dash-pot having a closed air-chamat the bottom andcontaining a body of air trapped in the air-chamber by the oil from thepiston-chamber, the piston having a re stricted passage permitting theoil to move through it, substantially as specified. I I

2. The dash-pot consisting of the piston, the piston-cylinder, andanair-chamber, the piston-cylinder being filled with oil and 'communicating at the bottom 'with thebottom of the air-chamber, and theoiLbeing free .to move from one side to the other of the piston througha restricted passage, substantially as specified.

3. The dash-pot consisting of the cylinder charged with oil on bothsides of the piston, 5. The dash-pot employing both air and a a pistonmoving in said cylinder and having body of oil as the cushioning agents,the air an oil-passage through it, and a closed airbeing confined in aclosed chamber by the oil,

chamber communicating with the cylinder and the oil being moved by thepiston, sub- 5 below the piston, substantially as specified. stantiallyas specified.

4. The dash-pot provided with an air-chamber exterior to itspiston-chamber and com- WILLIAM COLLIER BEAUVAIS' municating with thebottom thereof, said air- Attest: chamber having no opening for theadmission G. M. HERO, IO or escape of the air, substantially asspecified. .TNO. J. WARD.

